The Hoopa and Karuk tribes are raising concerns about a PacifiCorp Energy algae study that took place in the Copco Reservoir of the Klamath River this week.

According to PacifiCorp, the study is intended to look at whether a pesticide will knock down high levels of blue-green algae in the reservoir. The pesticide -- called aquatic algaecide -- is hydrogen peroxide and peroxyacetic acid-based.

"As it's being used, there's no scientific basis whatsoever to the notion that it poses any threat to fish, humans or other animals," PacifiCorp spokesman Bob Gravely said in an email.

The company applied the algaecide to a cove in the Copco Reservoir on Thursday.

PacifiCorp Klamath project manager Tim Hemstreet said it was the only application scheduled for now -- at least until PacifiCorp determines whether it is effective at killing the blue-green algae.

Representatives of the Hoopa and Karuk tribes said they are concerned about the effect it might have on the downriver and upset that they were not consulted by PacifiCorp before the test.

"We weren't even notified," said Regina Chichizola, a spokeswoman for the Hoopa Tribe, adding that ceremonies are planned on the river this week.

"There's a concern that when you kill toxic algae with a pesticide, it could release its toxins into the river," she said.

Clayton Creager, an environmental scientist with the California Water Quality Control Board, said the concern is not with the toxicity of algaecide itself. Rather, he said, the algaecide PacifiCorp used has the potential to oxidize the cell membrane in blue-green algae, releasing microcystis -- a toxin that poses human health risks. Creager said the PacifiCorp permit did not address the issue.

"I originally put a hold on the permit because I didn't think it was adequate," he said. "It's a poorly written permit."

Creager said he did not have the jurisdiction to reject the permit on those grounds.

"I told PacifiCorp, there's a ground swell here. People are upset," Creager said. "They chose not to listen to that."

An online petition against using algaecides in Klamath reservoirs on change.org garnered more than 250 supporters by Friday afternoon.

PacifiCorp's permit states that the study would take place on both the Copco and Iron Gate reservoirs -- although Hemstreet said the Copco reservoir is the only study location for now.

Creager said PacifiCorp's plan was to use the Iron Gate Reservoir as a backup location for the algaecide study if there was too much wind to conduct the test at Copco.

Crystal Bowman, water resources coordinator for the Karuk Tribe, wrote a letter to PacifiCorp saying that she was especially concerned about the algaecide if it was used in the Iron Gate reservoir, which empties directly onto Karuk land.

"Algaecides are not a sustainable, long-term solution to control toxic algae," she wrote in the letter. "The times of the year when the algaecide would be used coincides with the time of the year that World Renewal Ceremonies are occurring downstream of the dams."

Hemstreet and Gravely stressed the algaecide is safe, stating that it is approved by the Environmental Protection Agency.

"There are no public usage restrictions," Gravely said.

Hemstreet said discussing the study with the tribes was "not a requirement."

"Frankly, we don't think they'll be affected by this," he said. "They're 150 miles down the river."

Creager said he believes PacifiCorp has the right intent, to reduce the level of blue-green algae in their reservoirs. But he said more long-term solutions -- like a nutrient reduction program upstream from the reservoirs -- is a better option.

"But it's PacifiCorp's call, it's their liability," Creager said. "It's a tough problem for them, but this wasn't the solution."